Synchronized quartz crystal watch

ABSTRACT

A highly accurate watch, comprising a quartz crystal time base and a movement controlled by an oscillator regulated to run slightly fast and being periodically connected to the quartz crystal time base. In one embodiment, a pulse counter totals the number of pulses put out by the watch oscillator during its normal operation and activates means to stop the oscillator when a sufficient number of pulses equal to a fixed time period has been reached. A second counter totals the pulses from the quartz cyrstal time reference and reactivates the watch when the number pulses equals the fixed time period thereby wiping out accumulated time errors. In a second embodiment, the output from a balance wheel oscillator and a divided down time base frequency are fed to a flip-flop. The output square wave increases in width due to the frequency difference between the balance wheel and time base and is integrated by an RC circuit. A Schmitt trigger circuit and monostable multivibrator are coupled to the flipflop. so that the trigger circuit is activated for a fixed short time interval and stops the balance wheel through a solenoid. After elapse of the fixed time interval, the balance wheel starts again.

United States Patent [191 Zaisky et al.

7 [451 Apr. 30, 1974 WATCH SYNCHRONIZED QUARTZ CRYSTAL [21] Appl. No.:298,109

[52] US. Cl. 58/28 R, 331/183 [51] Int. Cl G04c 3/04 [58] Field ofSearch 58/23 R, 23 A, 23 V, 28 R,

[56] References Cited UNITED STATES PATENTS 3,631,669 H1972 Felrath58/28 D 3,451,210 6/1969 Helterline et a1, 5 8/26 PrimaryExaminerRichard B. Wilkinson I Assistant Examiner--Edith Simmons JackmonSET 20 BALANCE WHEEL RESET 22 CRYSTAL DMD OSCILLATOR ER [57] ABSTRACT Ahighly accurate watch, comprising a quartz crystal time base and amovement controlled by an oscillator regulated to run slightly fast andbeing periodically connected to the quartz crystal time base. In oneembodiment, a pulse counter totals the number of pulses put out by thewatch oscillator during its normal operation and activates means to stopthe oscillator when a sufficient number of pulses equal to a fixed, timeperiod has been reached. A second counter totals the pulses from thequartz cyrstal time reference and reactivates the watchwhen the numberpulses equals the fixed time period thereby wiping out accumulated timeerrors. In a second embodiment, the output from a balance wheeloscillator and a divided down time base frequency are fed to aflip-flop. The output square wave increases in width due to thefrequency difference between the balance wheel and time base and isintegrated by an RC circuit. A Schmitt trigger circuit and monostablemultivibrator are coupled to the flip-flop. so that the trigger circuitis'activated for a fixed short time interval and stops the balance wheelthrough a solenoid. After elapse of the fixed time interval, the balancewheel starts again.

4 Claims, 3 Drawing Figures mfyzz SYNCHRONIZED QUARTZ CRYSTAL WATCH Thisis a division of application Ser. No. 144,601 Filed May 18, 1972 and nowU.S. PatQNo. 3,756,014.

BACKGROUND OF THE INVENTION The present invention relates to timekeepingdevices and more particularly to a synchronized quartz crystal watch.

The use of a quartz oscillator of highly stable frequency in conjunctionwith a frequency divider to control the frequency of a slave oscillatorhas long been known, see Jones U.S. Pat. No. 3,110,853. However,

- the application of this desirable means of control to an electricwatchhas posed problems. One solution is described in U.S. Pat. No.3,553,957 whichpertains to a system wherein a counted-down crystaloscillatorfurnishes pulses to a stepping motor driving a display. Thesystem provides correction if the watch is running too fast or too slow.

Various other prior art proposals to exploit the accuracy of a highfrequency quartz time base for a watch are found in the U.S. Pat. ofNakai, No. 3,212,252, Imakashi, No. 3,363,410, Schaller, No. 3,282,042and Helterline, No. 3,451,210. The present invention however,represents-a new and improved arrangement utilizing a quartz crystaltime base to control the accuracy of a timekeeping device.

SUMMARY OF THE INVENTION This invention comprises a low frequencyoscillator such as a balance wheel which supplies pulses to a firstcounter. When the counter has totaled a number of pulses correspondingto a fixed time interval, a flip-flop is triggered, activating asolenoid to stop the balance wheel of the timekeeping device which isnormally regulated to run fast. A quartz crystal oscillator supplies adivided down output to a second counter which resets the flip-flop whenthe counter has totaled the number of pulses corresponding to the fixedtime interval. The solenoid is deactivated and the timekeeping devicestarts immediately thereby eliminating any accumulated errors.

In a second embodiment, pulses from a balance wheel and divided downquartz oscillator pulses are fed to a flip-flop which produces a squarewave output of increasing width due to the frequency difference betweenthe inputs. The output voltage is integrated by an RC network and aSchmitt trigger circuit is activated when the capacitor reaches thecircuits critical level. A solenoid is then activated for a fixed shorttime interval determined by a monostable multivibrator to stop thebalance wheel. After elapse of the time interval, the balance wheelresumes wheel.

Accordingly, it is an object of this invention to provide a new andimproved timekeeping device which is synchronized by a quartz crystaltime reference.

Another object of this invention is to provide a watch which -isnormally regulated to run fast and is synchronized at intervals toeliminate accumulated errors.

A further object of this invention is to provide a unique means forstopping the balance wheel of a watch for a fixed period of time andreleasing the balance wheel for oscillation as determined by the quartzsynchronizing frequency.

BRIEF DESCRIPTION OF THE DRAWINGS The above andother objects andadvantages of the present invention will be moreclearly seen when viewedin conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic diagram of a first embodiment of the invention;

FIG. 2 is a schematic diagram of a second embodiment of the invention;and

FIG. 3 illustrates the wave forms at point A on the output of theflip-flop in FIG. '2.

DETAILED DESCRIPTION OF THE INVENTION The invention as shown in FIGS. 1and 2 pertains to a quartz crystal watch having a balance wheel '10which is synchronized by a quartz crystal frequency standard 11. Sincethe details of such a watch, apart from the present invention, areconventional, they will not be discussed in detail herein. It iswell-known, for example,-that the balance wheel 10 is coupled to thedrive train for the watch and causes movement of the watch hands. Asynchronization of the watch in the interest of accuracy may, therefore,be achieved by regulating th movement of the balance wheel 10.

With reference to FIG. 1 of the drawings, the invention includes abalance wheel 10 having a spring finger 12 mounted on the periphery andextending outwardly therefrom. The balance wheel 10 normally oscillatesat a low frequency which is fed to a first counter 13. In a typicalcase, the balance wheel 10 will oscillate at a frequency of (3 e) H,,where e represents the fractional deviation of the balance wheel 10 fromthe precise frequency. The counter 13 is designed to count up to Npulses which corresponds theoretically to a fixed time interval. Therelationship between the number of.

pulses N and the deviation E is such that N l/e.

The counter 13 is connected to a flip-flop 14, the output of which isnormally low but goes high when counter 13 reaches N pulses. Thisactivates the solenoid 16 which forces movable member 17 forward intoengagement with spring finger 12 to stop the balance wheel 10. Normally,the balance wheel 10 would be halted at or near its maximum excursion.

The high frequency output from the quartz crystal time base 11 is fedthrough divider 18 to a second counter 19. The quartz frequency may beinitially in the 60 KHz range and then divided down to 3.000 Hz bydivider 18. When counter 19 reaches N pulses, the solenoid 16 isreleased and the watch starts immediately. Both counters 13 and 19 arereset when solenoid 16 is deactivated. The watch is designed to normallyrun fast so that any accumulated timing errors are erased when thebalance wheel 10 is stopped. The stopping is momentary so that noproblem arises when viewing the watch. It is to be further noted thatthe counters l3 and 19 may be combined in a single updown counter.

In the embodiment of FIG. 2, which is utilized with a quartz watchconstruction similar to that of FIG. 1,

pulses from the balance wheel 20 are fed to a flip-flop 21. The normalpulse rate from the low frequency balance wheel oscillator 20 is (3 +e)Hz, where e represents the fractional deviation from the precisefrequency due to the fact that the watch is regulated to run fast.

The quartz crystal oscillator 22 supplies high frequency pulses to adivider 23 where they are divided down to a precise output frequency of3.000 Hz. The quartz oscillator pulses are also fed to the flip-flop 21and the output therefrom is shown in Fig. 3. It is to be noted that thewidth of the square wave pulses 24 increase from W to W due to thefrequency difference between the balance wheel and crystal oscillator22.

The output voltage from flip-flop 21 is integrated by the combination ofresistor 26 and capacitor 27. When the capacitor voltage reaches thecritical level of the Schmitt trigger portion of circuit 28, thesolenoid 29 is activated for a short fixed time interval T determined bythe monostable multivibrator portion of circuit 28. Stop member 31 isdriven into engagement with the spring finger 32 to halt the oscillationafter the elapse of time T. While the value of T is not critical, itmust be less' than one-sixth second.

During a 24 hour period, the solenoid 29 must be ac-;

tivated to compensate for the number of seconds the watch is regulatedto run in the fast direction. The power consumption of the inventionisconsidered reasonable under these conditions since no continuouscorrection is used. For example,'if the watch runs 2 minutes per dayfast and the power consumption of the solenoid is 2 milliamperes at 1.5volts, the current drain will be 24 milliamperehours/year.

The time delay between turn off and turn on is so small as to beimperceptible to the user. The intermittent correction is, therefore,most advantageously employed. The invention as described above can alsobe used with conventional contact watch designs or electronic watcheswherein the driving amplifier is switched on and off. It is to beunderstood that the above-described arrangements are merely illustrativeexamples of the application. Numerous other arrangements may be readilydevised by those skilled in the art which will embody the principles ofthe invention and fall within the spirit and scope thereof.

We claim:

1. A synchronized watch comprising:

a low frequency oscillator for driving the watch, said oscillator beingregulated to run normally fast producing a deviation from the'precisefrequency in the pulses therefrom,

.a high frequency time base,

a divider coupled thereto for reducing the output from the time base toprovide highly accurate low frequency timing pulses,

means for combining the low frequency oscillator pulses and the timingpulses to provide a resultant output signal,

means responsive to the output signal to deactivate the low frequencyoscillator periodically for a fixed time period and to activate saidoscillator at the end of said period thereby intermittently correctingthe synchronized 'watch.

2. A synchronized watch in accordance with claim 1 wherein: Y

the low frequency oscillator -wheel, and,

the high frequency time base comprises a quartz oscillator.

3. A synchronized watch in wherein:

the means for combining pulses comprises a flip-flop coupled to the lowfrequency oscillator and to the frequency divider and,

the means for activating and deactivating the low' frequency oscillatorcomprises an integrator connected to the output of the flip-flop, atrigger circuit activated when the integrated output reaches apredetermined voltage level, and means for stopping the low frequencyoscillator for a predetermined time interval when the trigger circuit isactivated.

4. A synchronized watch in accordance with claim 3 wherein:

.the means for stopping the low frequency oscillator fora fixed timeperiod comprises a monostable multivibrator coupled to the triggercircuit, andsolenoid means responsive thereto to engage and stop the lowfrequency oscillator for a fixed time period determined by themultivibrator.

comprises a balance accordance with claim '1

1. A synchronized watch comprising: a low frequency oscillator fordriving the watch, said oscillator being regulated to run normally fastproducing a deviation from the precise frequency in the pulsestherefrom, a high frequency time base, a divider coupled thereto forreducing the output from the time base to provide highly accurate lowfrequency timing pulses, means for combining the low frequencyoscillator pulses and the timing pulses to provide a resultant outputsignal, means responsive to the output signal to deactivate the lowfrequency oscillator periodically for a fixed time period and toactivate said oscillator at the end of said period therebyintermittently correcting the synchronized watch.
 2. A synchronizedwatch in accordance with claim 1 wherein: the low frequency oscillatorcomprises a balance wheel, and, the high frequency time base comprises aquartz oscillator.
 3. A synchronized watch in accordance with claim 1wherein: the means for combining pulses comprises a flip-flop coupled tothe low frequency oscillator and to the frequency divider and, the meansfor activating and deactivating the low frequency oscillator comprisesan integrator connected to the output of the flip-flop, a triggercircuit activated when the integrated output reaches a predeterminedvoltage level, and means for stopping the low frequency oscillator for apredetermined time interval when the trigger circuit is activated.
 4. Asynchronized watch in accordance with claim 3 wherein: the means forstopping the low frequency oscillator for a fixed time period comprisesa monostable multivibrator coupled to the trigger circuit, and solenoidmeans responsive thereto to engage and stop the low frEquency oscillatorfor a fixed time period determined by the multivibrator.